Discovery of two giant viruses visible to the naked eye off Brazil

Last update December 20, 2021 at 07:42 PM

The two newly discovered biological viruses have a unique way of working that sets them apart from other viruses. They are able to synthesize many types of proteins including a wide range of proteins belonging to living things: amino acids. This discovery raises a question that was thought to be resolved. Are viruses living things?

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Viruses are found in two different places. One in a sediment at the bottom of the ocean relatively close to Brazil and the other in Lake Soda, two extreme environments for this type of organism. The team that discovered them named them tupanviruses. Tupan or Tupa is the name for the god of lightning in the mythology of the people of Guarani in South America.





Tupan virus under light microscope


Tupanviruses are at least 2.3 microns in size, which is about 23 times the size of an HIV-like particle. Giant viruses are capable of infecting many types of organisms including protists and amoeba. For humans, the tupanvirus would not pose a threat according to the researchers.

As a reminder, according to wikipedia:

  • A protist is a eukaryotic microorganism. It is therefore a eukaryote other than an animal (metazoan), fungus (eumycete) or plant. This group is very heterogeneous, both anatomically and physiologically.1. It brings together organisms with a so-called simple cellular organization, most often unicellular, sometimes multicellular but without specialized tissues. Some are autotrophic like protophytes, others are heterotrophic like protozoa. The term protista was coined by Ernst Haeckel.


  • An amoeba is a microorganism belonging to various groups of eukaryotic complex cells. In the use of the term, amoeba in fact designates organisms that are members of many groups of amoeboid protists of different eukaryotic taxa: Amoebozoa, Rhizaria, Heterokonta, Excavata and Opisthokonta: it is therefore not a monophyletic group but polyphyletic. Perhaps the common ancestor of all amoebae is also the common ancestor of all eukaryotes.



A live virus (or not)


Yes, if you don't know, viruses in general wouldn't be living things. The genetic complexity of tupanviruses seriously challenges this categorization among scientists. "Each tupanvirus, for example, has an important genetic instruction manual with about 1,5 million base pairs of DNA, more than what some bacteria have," explains co-author Bernard La Scola, virologist at Aix-Marseille University in France.


But other scientists say giant viruses aren't that different from their smaller relatives. Research by Frederik Schulz, of the Department of Energy's Joint Genome Institute in Walnut Creek, Calif., Suggests that these microscopic behemoths are regular viruses that have acquired additional genes from their hosts and should not be classified as living. .


Tupanviruses don't settle the controversy, but they challenge our preconceptions about what life is, says La Scola, the research team that made the discovery.



Discovery of two giant viruses visible to the naked eye off the coast of Brazil


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